高功率双层径向线螺旋阵列天线理论分析与数值模拟

研究了一种高功率双层径向线螺旋阵列天线.论文首先介绍该阵列天线的工作原理,然后从工作原理出发,设计中心频率为4.0 GHz的高功率双层径向线螺旋阵列天线,提出并研究了螺旋单元天线的磁耦合馈电,最后用有限元算法软件对阵列天线进行了数值模拟.模拟结果表明:该口径为320mm的天线在中心频率上可获得21.13dBi的增益,口径效率可达72.3％,在-12°≤θ≤12°的范围内轴向轴比值小于1.55;在3.8GHz~4.2GHz的频率范围内增益大于20.68dBi,口径效率大于69%,天线轴向轴比值小于1.7.     

16单元组合式矩形径向线螺旋阵列天线的设计

提出并研究了一种组合式矩形径向线螺旋阵列天线.介绍该天线的提出背景及工作原理,利用L型电磁组合探针设计和数值模拟了口径为180×180 mm的C波段16单元组合式矩形径向线螺旋阵列天线,并对其进行实验验证.模拟结果表明:该天线在中心频率4.0 GHz下,增益18.74 dB,轴向轴比值0.567;在3.8～4.0GHz的频率范围内增益大于18.27 dB,轴比大于0.567,反射系数小于0.2.实验结果表明:该天线在3.8～4.0 GHz的频率范围内增益大于17.5 dB,口径效率大于83%,驻波比小于1.5.     

三角形栅格矩形径向线螺旋阵列天线的设计

为了提高矩形径向线螺旋阵列天线的极化和匹配性能,将顺序旋转相位技术应用于天线的设计中,提出了一种12单元三角形栅格矩形径向线螺旋阵列天线(子阵).螺旋天线作为单元天线.设计结果表明:天线具有较高的口径效率和良好的匹配特性,能在一定频带内实现微波的圆极化定向辐射,将多个子阵组合就可以构成高增益的大型阵列.同时,通过对子阵的特殊设计,使其具有较高的功率容量,为高功率微波的定向辐射提供了新的技术手段.     

基于双径向线的低剖面径向线螺旋天线

在卫星收发系统中,圆极化天线是一种重要的器件,负责信号的接收和发送。而径向线螺旋天线是一种重要的圆极化天线,但为实现圆极化性能,天线高度需达到0.15λ。通过引入主径向线和副径向线之间的耦合,减小了天线的高度,从而实现了低剖面的径向线螺旋天线。通过在馈电结构中引入贴片电容,从而改善了天线的阻抗匹配性能。所提出的径向线螺旋天线的高度为0.0525λ,仅为传统径向线螺旋天线高度的34%。为验证理论预期的可实现性,设计了基板为FR4、中心频率在1.54 GHz的低剖面径向线螺旋天线。实验结果表明,该天线的实测10-d B匹配带宽和3-d B轴比带宽分别为900 MHz和27 MHz,实测增益在2.9 d Bi,能够满足卫星接收天线的收发要求。     

用于高功率微波测量的圆极化微带阵列天线

在进行高功率微波(HPM)辐射场测量时,测量天线的极化匹配对测量精度影响较大。为提高测量精度,介绍一种微带圆极化阵列天线,采用功分器作为馈电网络,获得了小于1 d B的轴比,与非阵列圆极化微带天线相比,使轴比降低约1 d B。因此,当采用该圆极化阵列天线测量线极化微波的远场辐射时,使极化失配对测量结果的影响由±13%降至±3.6%左右。     

毫米波空馈径向线缝隙阵列天线的优化设计北大核心CSCD

本文设计了一种毫米波空馈径向线缝隙阵列（RLSA）天线。首先采用空气波导取代介质波导以降低天线的馈电损耗,接着分析加载辐射缝隙对造成径向线波导的慢波传输效应,以及不同长度的缝隙对引起的不同辐射相位滞后,然后修正各辐射单元之间的径向距离,以使口径面上所有缝隙对单元能够等幅同相地辐射。这一修正避免了栅瓣的产生,在35GHz工作频率和直径为10个波长的圆口径上实现了53.3%的口径效率。之后,放松各单元等相位辐射的要求,进一步减小单元径向间距Sρ,优化口径效率。最终研制出左旋圆极化RLSA天线,峰值增益达到27.71dBic,口径效率为59.8%,3dB增益带宽为8.37%;实测增益为27.51dBic,轴比0.46dB。     

L波段高功率线极化径向线阵列天线优化设计

针对L波段高功率线极化径向线阵列天线进行了优化设计.分析了影响阵列天线口径效率的因素,通过三种途径优化了口径效率;同时对单元天线进行适当的优化,减小了阵列天线的反射,提高了阵列天线的整体性能,使其更好地应用于实际.模拟结果表明:经过改进后,阵列天线的口径效率从原来的50.57%提高到85.1%,中心频率上的反射系数降为0.1146,且在513兆赫兹的频率范围内反射系数都小于0.2.     

同轴电探针耦合测高功率微波

本文从理论上对同轴电探针耦合检测高功率微波进行了简明的分析，推导了在国波导中传输TM（mn）和T（mn）模耦合度的计算公式。设计了一种同轴电探针，并用此探针近似测量虚阴极振荡高功率微波发生器产生的单次脉宽30ns的高功率微波，测得X波段脉冲峰值功率为1GW左右。此种测量高功率微波的方法虽不很精确，但作为一种监测的手段，具有结构简单，使用方便等特点。     

高功率微波照射下阿基米德螺旋天线响应特性

天线在高功率微波辐照下的响应特性分析是研究后端接收电路干扰特性及毁伤效应的依据。以典型的平面阿基米德螺旋天线为研究对象,利用理论分析和时域有限积分方法相结合,研究了该天线在高功率微波场作用下的时域和频域响应特性,并开展了相关的试验验证。结果表明,通过Friis 传输理论预估的发射功率和实际发射功率的误差在1 dB 量级,仿真得到的响应信号和测试得到的响应信号在时域波形和频谱特性上均吻合较好,仿真方法正确有效,为高功率微波照射下天线响应特性的研究提供了技术支撑。     

高功率阵列半导体激光器的光纤耦合输出

采用柱透镜对10单元阵列半导体激光器的输出光束进行了有效收集和预准直及多模光纤之间的耦合实验。激光器采用808nm波长、150μm条宽的发射单元,周期为1000μm,与200μm芯径平端光纤阵列的耦合效率高达75％,光纤输出功率7．5W,分析了影响耦合效率的主要因素。     

Low-profile helical array antenna fed from a radial waveguide

A low-profile array antenna composed of two-turn 4° pitch angle helices is designed for a frequency band of 11.7 GHz to 12.0 GHz. The feed wire of each helix is inserted into a radial waveguide through a small hole and excited by a traveling wave flowing in the transverse electromagnetic mode between the two parallel plates of the waveguide. The measured aperture efficiency shows a maximum value of 77% for a beam radiated in the normal direction and 69% for a 30° beam tilt     

60 GHz band radial line slot array antenna fed by rectangularwaveguide

A single-layered radial line slot array (SL-RLSA) antenna etched on a substrate and fed by a rectangular waveguide is presented in the 60 GHz band. The design curves are obtained by an efficient electromagnetic coupling analysis using Ewald sum technique and Shanks' transformation. The antenna has rectangular waveguide feed structure using a rectangular waveguide-to-radial line transition. The prototype antenna of 10 cm diameter was tested and the gain of 30 dBi was measured at 60 GHz     

Aperture coupled beam steering microstrip antenna array fed bydielectric image line

Five- and eight-element patch antenna arrays linearly fed by dielectric image lines have been developed with good E-plane and H-plane patterns. The measured results and the calculated beam steering angles agree very well. Crosspolarisations are 20 dB and side lobes are 15 dB below the main lobe     

Design of aperture coupled microstrip antenna array fed bydielectric image line

A novel design for a linear array of microstrip antennas, aperture coupled to a dielectric image line has been developed. The design is based on a simplified theory to determine the impedances of the antennas at their apertures, and in turn, the coupling to each antenna from the image line. The theory developed is verified using an eight-element linear array and the experiment results are very good     

Dual band aperture coupled antenna using spur line

A new dual band microstrip antenna is presented. A spur line is embedded in the nonradiating edges of the patch to obtain dual band operation at two separate frequencies with good radiation characteristics. Very good agreement between the simulation and the measurements is obtained     

An electromagnetic-field method modeling of a radial line planar antenna with coupling probes

This communications describes an electromagnetic model of a radial line planar antenna consisting of a radial guide with one central probe and many peripheral probes arranged in concentric circles feeding an array of antenna elements such as patches or wire curls. The model takes into account interactions between the coupling probes while assuming isolation of radiating elements. Based on this model, computer programs are developed to determine equivalent circuit parameters of the feed network and the radiation pattern of the radial line planar antenna. Comparisons are made between the present model and the two-probe model developed earlier by other researchers.     

Circularly polarised patch antenna array using proximity-coupledL-strip line feed

A microstrip antenna array for circular polarisation (CP) using a proximity L-strip line feed is proposed and experimentally investigated. By placing a cross-slot with unequal slot lengths on the circular patch, circular polarisation can be excited. Also, a sequential rotation technique is adopted for the design of this CP antenna array to widen the bandwidth. The impedance and axial ratio bandwidth values are 78 and 16.15%, respectively. The boresight axial ratio is 0.4 dB at 1.91 GHz     

The development of radial line slot array antenna for direct broadcast satellite reception

Microwave antennas are extensively used in communications systems such as satellite, television and high-speed data transmission due to their wide and absolute bandwidth. Among the variety of microwave antennas, satellite communication commonly adopts an antenna of parabolic dish type, despite some drawbacks. In a primary fed design, there is considerable aperture blockage. An offset parabolic antenna design, which then eliminates the blockage, is susceptible to physical damage as its feed is significantly exposed from the body of reflector. The radial line slot array (RLSA) type antenna is thus designed to cope with the problems encountered in parabolic antennas. RLSA is a planar antenna suitable for direct broadcast satellite (DBS) reception, with advantages including high radiation efficiency (high gain), low profile, low cost and feed rear-mounted. The prototype development started with the selection of the cavity's dielectric material and construction of the feeding structure of coaxial-to-waveguide transition. Within the frequency band of interest, between 10.95 and 11.7?GHz, results, is showed a lower than ?10?dB of return loss. A DBS receiver test-bed had been developed to test the constructed antenna prototypes and it revealed that the prototype has the capability of receiving TV programs from DBS.